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Syfte: Den aktuella studien är en metodstudie för att undersöka möjligheten att mäta förändringar i muskeltjocklek med ultraljud. Om detta fungerar kan metoden användas i studier som för närvarande undersöker om muskeltjocklek eller förändringar i muskeltjocklek vid användning är relaterade till orofacial smärta.Material och metod: Tjugotvå friska forskningsindivider undersöktes. Alla forskningsindivider svarade negativt på de tre screeningfrågorna för temporomandibulär dysfunktion. Ultraljudsundersökningen utfördes för att utvärdera massetermuskelns och temporalismuskeln tjocklek (tjockaste delen och på en standardiserad plats för varje muskel) bilateralt som ett surrogatmått för det totala muskelblodflödet i vila och under hopbitning före och efter en tuggövning. Individen skulle tugga tre smaklösa paraffintuggummi med en frekvens av 90 Hz (90 tugg per minut) under 5 minuter. Individen svarade också på tre frågor om muskelsmärta, trötthet och obehag före och efter tuggövningen.Resultat: Vid jämförelse av muskeltjockleken i vila kontra hopbitning, både före och efter tuggövningen, var resultaten att massetermuskeln är tjockare vid hopbitning än vid vila. Resultaten var signifikant för masseter men inte för den temporalis. Resultaten avseende NRS-skalorna, som visade en ökning i värde efter tuggövningen, var enligt den statistiska analysen signifikanta.Slutsats: Denna studie visar att bedömning av muskeltjocklek med ultraljud är möjlig för masseter eftersom metoden kan upptäcka skillnader mellan vila och hopbitning. / Aim: The current study is a proof-of-concept study to investigate the possibility to measure changes in muscle thickness with ultrasound. If this works, the methodology can be used in studies that are currently investigating whether muscle thickness or changes in muscle thickness in use are related to orofacial pain. Materials and method: Twentytwo healthy research individuals were examined. All of the research individuals answered negatively on the three screening questions for temporomandibular disorders. The ultrasound examination was performed to assess masseter and temporal muscle thickness (thickest part at one standardized location for each muscle) bilaterally as a surrogate measure of total muscle blood flow at rest and during clenching before and after a chewing exercise. The subject would chew three paraffin wax taste-less chewing gums at a frequency of 90 Hz (90 chews per minute) for 5.0 minutes. The subject also answered three questions about muscle pain, fatigue and discomfort before and after chewing. Result: When comparing the muscle thickness at rest versus clenching, both before and after the chewing exercise, the results were that the masseter muscle is thicker when clenching than at rest. The difference was significant for the masseter but not for the temporal muscle. The results obtained regarding the NRS-scales, which showed an increase in value after the chewing exercise was according to the statistical analysis significant. Conclusion: This study shows that assessment of muscle thickness with ultrasound is feasible for the masseter muscle since the method is capable of detecting differences between rest and clenching.

Bruxism är en vanemässig parafunktion som ofta delas in i två skilda fenomen, tandpressning och tandgnissling. Tandpressning anses vara kopplat till dagen och natten medan tandgnissling till natten. Bruxismens etiologi förklaras antingen med den mekaniska eller den psykologiska teorin. I dagsläget finns ingen definitiv metod för att registrera bruxism, som både har klinisk validitet i diagnostiseringen och som är kostnadseffektiv. Syftet med denna studie är att visa om bruxism är en förutsägbar parafunktion som är ihållande från barndom till vuxen ålder. Dessutom ska en redogörelse av hur bruxism påvisas av tandvårdspersonal klargöras. Metoden har varit att studera artiklar, bearbeta innehållet för att därefter välja ut det mest passande för syftet. Artiklarna är baserade på longitudinella epidemiologiska studier utförda i Sverige. Informationen redovisas i en tabell. Hälsodeklarationer har insamlats från fem avdelningar på Malmö Tandvårdshögskola samt Folktandvården. Resultat visar att av totalt åtta artiklar visar samtliga att bruxism är ihållande från barndom till vuxen ålder. Två avdelningar på Malmö Tandvårdshögskola disponerar frågor i hälsodeklarationen gällande bruxism. Slutsatsen blir därför att bruxism är en förutsägbar parafunktion som är ihållande från barndom till vuxen ålder, men livssituationen och medvetenheten om sin vana är avgörande faktorer. Tandvårdspersonal kan upptäcka patienter där bruxism har lett till smärta och funktionsstörningar genom att ställa frågorna: 1) Har du smärta i ansiktet, käken, tinningen, framför örat eller i örat en gång i veckan eller oftare? 2) Har du ont när du gapar, eller tuggar en gång i veckan eller oftare? / Bruxism is a habitual movement, which is often divided into two different phenomena; clenching and grinding. Clenching is considered to occur during day- and nighttime while grinding is more prevalent during sleep. The etiology of bruxism is explained either by the mechanical theory or the psychological theory. Currently there is no definitive way of determining bruxism, that both has validity in diagnosis and that is cost-effective at the same time. The aim of this study was to evaluate if bruxism could be predicted from childhood to adulthood. Furthermore identify how bruxism can be discovered by dental practitioners.The method has been to study articles, value the content and after that choose those articles that would be most suitable for our aim. The articles is based on longitudinal epidemiological studies made in Sweden. The information that was found is introduced in a table. Health declarations has been collected from five departments at Malmö Tandvårdshögskola and Folktandvården. Results in eight articles show that bruxism is a predictable parafunction that is persistent from childhood to adulthood. Two departments at Malmö Tandvårdshögskola disposes questions related to bruxism. Therefore it is concluded that bruxism is a predictable parafunction that is persistent from childhood to adulthood, but the living conditions and awareness of the habit are key factors. Dentistry staff can identify patients where bruxism have led to pain and dysfunction by asking following questions 1) Do you have pain in the face, jaw, temples, in front of the ear or in the ear once a week or more often? 2) Do you have pain when you open your mouth, or chew once a week or more?

A major physiological risk factor of temporomandibular disorders (TMD) is sensitization of peripheral and central nervous system pain processing pathways. Calcium channel, voltage-dependent, alpha-2/delta subunit-1 (CACNA2D1) has a crucial role in relaying nociceptive information in the spinal dorsal horn. Up-regulation of CACNA2D1 results in abnormal excitatory synapse formation and enhanced presynaptic excitatory neurotransmitter release. Blocking CACNA2D1 with gabapentinoid-class drugs relieves orofacial hypersensitivity. Drs. Foley, Horton, and Sciote previously reported that in a small sample group (n=12), CACNA2D1 expression was greater in males than females, but increased in women with TMD. The objectives of this study are to corroborate these data and investigate expression patterns of other ion channel and conducting system genes. Additionally, since the null polymorphism ACTN3-577XX associates with muscle fiber microdamage during eccentric contraction, we tested for possible gene associations with ACTN3-R577XX genotypes. Masseter muscle samples came from human subjects (n=23 male; 48 female) with malocclusions undergoing orthognathic surgery. This population had skeletal disharmony of the jaws and thus was prone to eccentric contraction. Three males and eighteen females were diagnosed with localized masticatory myalgia. Muscle total RNA was isolated and CACNA2D1, CACNA1S, GABARAP, and TRPM7 expression was quantified using RT-PCR. Expression of these genes were compared based on TMD status and various characteristics that may influence TMD including: sex, age, facial symmetry, sagittal dimension, vertical dimension, ACTN3-577 genotype and fiber type. CACNA2D1 expression differed significantly between sexes, overall (p<0.02), and without TMD (p=0.001). Women with (n=13) and without (n=23) TMD differed significantly (p<0.03). CACNA2D1 expression was also significantly higher (p=0.031) in subjects below age 25. Similarly, GABARAP expression was significantly higher (p=0.001) for patients younger than 25 and for patients less than or equal to age 18 (p=0.013). Otherwise, CACNA1S, TRPM7 and GABARAP differences were not significant. GABARAP expression differed, but not significantly by sex and for the ACTN3-577XX-null genotype. In a population of malocclusion patients, masseter muscle CACNA2D1 expression is significantly higher than CACNA1S, TRPM7, and GABARAP. CACNA2D1 expression is greater in males than females without TMD. However, CACNA2D1 expression increases significantly in females with TMD-associated myalgia. This may support evidence for calcium channel regulation of nociception differences seen between sexes in TMD. It was also found that expression of CACNA2D1 and GABARAP is significantly higher in younger subjects. Additionally, observations presented here suggest potential influence of ACTN3-null condition on function of GABARAP. / Oral Biology

Temporomandibular disorders (TMD) are comorbid conditions. Most are related to anxiety-induced muscular pain, but some are associated with facial asymmetry resulting from condylar resorption (CR) or condylar hyperplasia (CH). The etiology of the most common forms of CH and CR are still unknown. CR can be caused by rheumatoid arthritis (RA) or more commonly osteoarthritis (OA) of the TMJ, and inflammatory mediators have been previously implicated. Previous studies have identified pain/inflammatory genes related to chronic TMD while others have demonstrated potential genetic markers for RA. Similarly, genome-wide association (GWA) studies have identified genes associated with height, some of which may participate in craniofacial growth, CH, and the development of asymmetry. Masseter muscle is frequently involved in TMD of muscular origin, and left/right fiber-type differences have been previously found in subjects with facial asymmetry. A human transcriptome microarray was used to evaluate whether genes involved with height, pain, or inflammation were differentially expressed in masseter muscle from facially asymmetric patients with and without TMD. This study evaluated orthognathic surgery patients with varying skeletal malocclusions, including subjects with and without facial asymmetry and TMD (n= 93). Masseter muscle samples were collected from ten orthognathic surgery patients treated to correct skeletal malocclusions. Two of whom were classified with facial asymmetry with or without TMD, with one of the two showing positive evidence of CR. Samples were disrupted in QIAzol Lysis Reagent, RNA was isolated using a Qiagen miRNeasy Mini Kit according to the manufacturer's instructions, and quality of the total RNA was tested by Agilent Bioanalyzer and Nanodrop spectrophotometry. Samples were used for quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and protocols for microarray analysis were conducted as described in the Ambion WT Expression Manual and the Affymetrix GeneChip Expression Analysis Technical Manual. Principal Components Analysis (PCA) was completed to detect fold-changes for each transcript to determine differences in global gene expression between the two asymmetric and eight remaining subjects. To find differentially expressed transcripts step-up t-tests were performed to correct for false discovery rate (FDR) comparing the two asymmetric samples to the eight symmetric samples. Differences were considered significant if step-up p-values were ±2 between groups. This study evaluated 847 height-related genes and 551 genes associated in pain/inflammatory processes. Genes of interest were determined a priori from GWA studies and the Algynomics Pain Research Panel v.2.0 partially derived from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study. Two hundred and eight transcripts of 847 height associated genes and 132 of 551 pain/inflammatory genes were significant for expression (P±2.0 fold differences in facial asymmetry and/or TMD specimens. Among genes specifically reported to be associated with pain/inflammation, NPY5R (+2.11 fold), GABRA6 (+2.14 fold), CACNA2D1 (-12.51 fold) and EREG (+2.12 fold) showed significantly different (P<0.001) expression levels in the two asymmetric versus the remaining eight symmetric patients. CACNA2D1 expression was significantly increased in symmetric male subjects versus symmetric females (P < 0.05) as well as in asymmetric females versus asymmetric males (P < 0.05). CACNA2D1 expression was also significantly increased in symmetric male subjects versus symmetric females (P <0.05) and was differentially expressed at lower levels, however not significantly, in asymmetric males (p = 0.51). Based on the results collected, the following conclusions were drawn. These methods provide a novel approach to study TMD and/or facial asymmetry in human subjects. To our knowledge, this is the first study to demonstrate that significant expression variation in human height genes may contribute to facial asymmetry with or without TMD, possibly through decreased expression of CACNA2D1. These data suggest TMD patients with facial asymmetry associated with condylar resorption may show significant differential expression of certain inflammatory marker genes such as EREG and CACNA2D1. These data support that gender may play a key role in the development of TMD, possibly through increased CACNA2D1 expression providing protective effects in TMD-free males but deleterious effect in females with TMD. These results support previous findings of pain/inflammatory genes associated with TMD derived from muscular pain. Further studies are needed to understand the genetic contributions to TMD, which may play an important role in future clinical intervention. / Oral Biology

In recent years, two-dimensional (2D) van der Waals (vdW) materials have aroused much interest for their unique structural, thermal, optical, and electronic properties and have become a hot topic in condensed matter physics and material science. Many research methods, including scanning tunneling microscopy (STM), transmission electron microscopy (TEM), optical and transport measurements, have been used to investigate these unique properties. Among them, STM stands out as a powerful characterization tool with atomic resolution and is capable of simultaneously revealing both atomic structures and local electronic properties. This dissertation focuses on scanning tunneling microscopy and spectroscopy (STM/S) investigation of 2D metal chalcogenides and heterostructures. The first part of the dissertation focuses on the continuous interface in WS2/MoS2 heterostructures grown by the chemical vapor deposition (CVD) method. We observed a closed interface between the MoS2 monolayer and the heterobilayer with atomic resolution. Furthermore, our scanning tunneling spectroscopy (STS) results and density functional theory (DFT) calculations revealed band gaps of the heterobilayer and the MoS2 monolayer agree with previously reported values for MoS2 monolayer and MoS2/WS2 heterobilayer on SiO2 fabricated through the mechanical exfoliation method. The results could deepen our understanding of the growth mechanism, interlayer interactions and electronic structures of 2D transition metal dichalcogenides (TMD) heterostructures synthesized via CVD. The second part of the dissertation focuses on phase transformation in 2D In2Se3. We observed that 2D In2Se3 layers with thickness ranging from single to ~20 layers stabilized at the beta phase with a superstructure at room temperature. After cooling down to around 180 K, the beta phase converted to a more stable beta' phase that was distinct from previously reported phases in 2D In2Se3. The kinetics of the reversible thermally driven beta-to-beta' phase transformation was investigated by temperature dependent transmission electron microscopy and Raman spectroscopy, combined with the expected minimum-energy pathways obtained from our first-principles calculations. Furthermore, DFT calculations reveal in-plane ferroelectricity in the beta' phase. STS measurements show that the indirect bandgap of monolayer beta' In2Se3 is 2.50 eV, which is larger than that of the multilayer form with a measured value of 2.05 eV. Our results on the reversible thermally driven phase transformation in 2D In2Se3 will provide insights to tune the functionalities of 2D In2Se3 and other emerging 2D ferroelectric materials and shed light on their numerous potential applications like non-volatile memory devices. The third part of the dissertation focuses on domain boundaries in 2D ferroelectric In2Se3. The atomic structure of domain boundaries in two-dimensional (2D) ferroelectric beta' In2Se3 is visualized with scanning tunneling microscopy and spectroscopy (STM/S) combined with DFT calculations. A double-barrier energy potential across the 60° tail to tail domain boundaries in monolayer beta' In2Se3 is also revealed. The results will deepen our understanding of domain boundaries in 2D ferroelectric materials and stimulate innovative applications of these materials. / Doctor of Philosophy / Two-dimensional (2D) materials are materials consisting of a single layer or a few layers of atoms. They exhibit unique and interesting properties distinct from their bulk counterparts. Over the past decade, much effort has been devoted to a large family of 2D materials — 2D metal chalcogenides that exhibit fascinating structural and electronic properties. These 2D metal chalcogenides can also be stacked together to form various heterostructures. The scanning tunneling microscope (STM) is a powerful tool to study these materials with atomic resolution and is capable of simultaneously revealing both atomic structures and local electronic properties. It can also be used to manipulate nanometer-scale structures on the material surface. In this dissertation, we use scanning tunneling microscopy and spectroscopy (STM/S) to investigate 2D metal chalcogenides and heterostructures. The first part of the dissertation focuses on WS2/MoS2 heterostructures grown by the chemical vapor deposition (CVD) method. We observed a closed interface between the MoS2 monolayer and the heterobilayer with atomic resolution. Furthermore, our scanning tunneling spectroscopy (STS) results and density functional theory (DFT) calculations revealed band gaps of the heterobilayer and the MoS2 monolayer. The results could deepen our understanding of the growth mechanism, interlayer interactions and electronic structures of 2D transition metal dichalcogenides (TMD) heterostructures synthesized via CVD. The second part of the dissertation focuses on phase transformation in 2D In2Se3. We observed that 2D In2Se3 layers transform from beta phase to a more stable beta' phase when the sample is cooled down from room temperature to 77 K. This thermally driven beta-to-beta' phase transformation was found to be reversible by temperature dependent transmission electron microscopy and Raman spectroscopy, corroborated with the expected minimum-energy pathways obtained from our first-principles calculations. Furthermore, DFT calculations reveal in-plane ferroelectricity in the beta' phase. Our results on the reversible thermally driven phase transformation in 2D In2Se3 will provide insights to tune the functionalities of 2D In2Se3 and other emerging 2D ferroelectric materials. The third part of the dissertation focuses on domain boundaries in 2D ferroelectric In2Se3. The atomic structure of domain boundaries in 2D ferroelectric beta' In2Se3 is visualized by using STM/S combined with DFT calculations. A double-barrier energy potential across the 60° tail to tail domain boundaries in monolayer beta' In2Se3 is also revealed. The results will deepen our understanding of domain boundaries in 2D ferroelectric materials and stimulate innovative applications of these materials.

This work is focused on the study of luminescence of atomic thin layers of transition metal chalkogenides (eg. MoS2). In the experimental part, the work deals with the preparation of atomic thin layers of semiconducting chalcogenides and the subsequent manufacturing of plasmonic interference structures around these layers. The illumination of the interference structure will create a standing plasmonic wave that will excite the photoluminescence of the semiconductor. Photoluminescence was studied both by far-field spectroscopy and near-field optical microscopy.

Syfte: Det saknas kunskap om samband mellan vaginism och bruxism. Syftet med studien var att studera förekomst av orala parafunktioner och bruxism hos kvinnor med vaginism i jämförelse med kvinnor utan vaginism. Studien syftar även till att undersöka eventuella skillnader kring smärta, stress och somatiska besvär mellan grupperna. Metod: En enkätstudie där en modifierad version av DC/TMD axel II, delades ut till patienter som sökt barnmorska. Resultat: Bland de 26 svarande fanns en tendens till ökade dagliga parafunktioner som att pressa tänder under vaken tid, vilket kunde ses i deltagargruppen med vaginism i jämförelse med kontrollgruppen. Smärta som skulle kunna relateras till TMD och parafunktioner var mer frekventa samt mer uttalade i deltagargruppen med vaginism. Deltagargruppen med vaginism hade även en antydan till mer stress, oro samt somatiska besvär.Konklusion: Den viktigaste slutsatsen utifrån utförd studie är att det inte tydligt skiljer sig mellan en grupp individer med vaginism och en kontrollgrupp avseende bruxism. Deltagargruppen med vaginism har en tendens till mer förekommande orala parafunktioner. TMD smärta är mer förekommande i deltagargruppen med vaginism vilket eventuellt kan vara en orsak av ökade parafunktioner. Båda grupperna hade förekomst av psykosociala riskfaktorer för bruxism, dock var de något mer frekventa i experimentgruppen. Det finns ingen tidigare forskning kring sambandet mellan vaginism och bruxism varvid denna studie med endast ett fåtal deltagare skulle kunna ses som en pilotstudie, vilken kan bidra till att öppna upp för interdisciplinär forskning i ämnet. / Aim: There is a lack of knowledge regarding the relationship between vaginismus and bruxism. The purpose of the study was to investigate the occurrence of bruxism and oral parafunctions in women with vaginismus in comparison to women without vaginismus. The study also aimed to investigate possible differences in pain, stress and somatic disorders between the groups.Method: The survey was executed with a modified version of DC/TMD Axis II, and was distributed to patients seeking care from a midwife.Results: Among the 26 respondents, there was a tendency for increased parafunctions, such as clenching teeth during awake time in the vaginismus group of participants. Pain that could be related to TMD and parafunctions were more frequent and more apparent in the group with vaginismus. The group with vaginismus also had a hint of more stress, anxiety and somatic problems.Conclusion: The most important conclusion from the study is that there is no clear difference between a group of individuals with vaginismus and a control group regarding TMD. The group with vaginismus had a tendency of more oral parafunctions. TMD pain is more common in the group with vaginismus, which might be caused by increased parafunctions. Both groups had psychosocial risk factors for bruxism, however, they were somewhat more frequent in the experimental group. There is no previous research on the relationship between vaginismus and bruxism, this study with only a few participants could be seen as a pilot study, which could help open up interdisciplinary research on the subject.

Syfte Syftet med föreliggande studie var att undersöka böjhållfastheten på 3D-printat material avsett för stabiliseringsskenor som är tillverkade i olika vinklar och både före och efter polering. Material och Metod Totalt framställdes 50 rektangulära provkroppar i vinklarna 0°, 25°, 45°, 75° och 90° med måtten 64 x 10 x 4,5 mm av Keysplint Hard och hälften polerades med Otec poleringsmaskin. Alla provkroppar utsattes för ett trepunktsböjhållfasthetstest med Instron 4465 med en lasthastighet på 5 mm/min till fraktur och värdena dokumenterades i Bluehill-mjukvara. Resultatet analyserades med One-Way ANOVA, Tukey s’ test och signifikansnivån sattes till α = 0,05. Resultat Enligt resultat från programmet SPSS (IBM® SPSS® Statistics powerful statistical software platform) observerades högst böjhållfasthet i den 3D-printade gruppen vid 25° som var polerad, vilket innebar en signifikant skillnad mellan denna grupp (25°) och de övriga grupperna (p<0,05). Statistisk påvisades inga signifikanta skillnader mellan de andra grupper oavsett om det var opolerade och polerade provkroppar printade i vinklarna 0॰, 45॰, 75॰,90॰ (p>0,05). Slutsats Inom ramen för studiens begränsningar kan följande slutsats dras: Printningsvinkel och polering påverkar böjhållfastheten hos 3D-printad polymer. En printningsvinkel på 25॰ i kombination med polering ger högst böjhållfasthet. En printningsvinkel på 0॰ger numeriskt lägst böjhållfasthet. Mer omfattande studier beträffande olika printningvinklar, olika printningsmaterial (resin) och 3D-printrar och dess inverkan på böjhållfastheten krävs för att säkerställa resultaten. / Aim The purpose of this in vitro study was to investigate the flexural strength of 3D-printed material intended for stabilization splints that are manufactured at different angles, both before and after polishing. Material and Method A total of 50 rectangular specimens at angles of 0°, 25°, 45°, 75° and 90° with dimensions of 64 x 10 x 4.5 mm were produced by Keysplint Hard and half were polished with the Otec polishing machine. All specimens were subjected to three-point flexural strength test using the Instron 4465 at a loading rate of 5 mm/min to fracture and the values were documented in Bluehill software. The result was analyzed with One-Way ANOVA, Tukey's test and the significance level was set at α = 0.05. Results According to results from the software SPSS (IBM® SPSS® Statistics powerful statistical software platform), the highest flexural strength was observed in the 3D-printed group at 25° that was polished, which means a significant difference between this group (25°) and the other groups (p<0.05). Statistically, no significant differences were detected between the other groups regardless of whether they were unpolished and polished specimens printed at angles 0°, 45°, 75°, 90° (p>0.05). Conclusion Within the limitations of the study, the following conclusion can be drawn: Printing angle and polishing affect the flexural strength of 3D-printed polymer. A printing angle of 25° in combination with polishing gives the highest flexural strength. A printing angle of 0° gives the numerically lowest flexural strength. More extensive studies regarding different printing angles, different printing materials (resin) and 3D-printers and the effect on the flexural strength are required to ensure the results.